The venous admixture was measured before, during, and after deflation of one lung during anaesthesia for thoracotomy in 10 subjects ventilated with 50% oxygen. The mean oxygen saturation fell from 99% before deflation of the lung to 89% after 30 minutes’ atelectasis. The pH and carbon dioxide tension did not change significantly. The shunt was 38% of cardiac output five minutes after and 41% 30 minutes after deflation. The reciprocal of the arterial venous oxygen content difference correlated positively with the shunt, suggesting that increased venous admixture is accompanied by increased cardiac output.
References
1.
BarthL., HolmdahlM. H., LofB., ObrinkK. J., and UlfendahlH. (1957): “Ventilation of the lungs and acid base balance in thoracic surgery”, Acta Chir. Scandinav., 113, 413.
2.
BeecherH. K., and MurphyA. J. (1950): “Acidosis during thoracic surgery”, J. Thor. Surg., 19, 50.
3.
BjorkV. O. (1953): “Circulation through an atelectatic lung in man”, J. Thor. Surg., 26, 533.
4.
BrunerJ. M. R. (1967): “Hazards of electrical apparatus”, Anesthesiology, 28, 397.
5.
KanekoK., Milic-EmilyJ., DolovichM. B., DawsonA., and BatesD. V. (1966): “The regional distribution of ventilation and perfusion as a function of body position”, J. Appl. Physiol., 21, 767.
6.
LoughmanJ., and WatsonA. B. (1971) “Electrical safety in Australian hospitals and proposed standards”, Med. J. Aust. (In press.)
7.
LundingM., and FernandesA. (1967): “Arterial oxygen tension and acid base status during thoracic anaesthesia”, Acta anaesth. Scandinav., 11, 43.
8.
MichenfelderJ. D., FowlerW. S., and TheyeR. A. (1966): “Carbon dioxide levels and pulmonary shunting in anaesthetised man”, J. Appl. Physiol., 21, 1471.
9.
NilssonE., SlaterE. M., and GreenbergJ. (1965): “The cost of the quiet lung”, Acta anaesth. Scandinav., 9, 49.
10.
SchankW. G., McDonaldK. E., and KennedyP. A. (1963): “Direct measurements of human pulmonary haemodynamics during thoracotomy”, Ann. Surg., 157, 298.
11.
SteadW. W., MartinF. E., and JansenN. K. (1953): “Physiological studies following thoracic surgery. IV. The development of acidosis during anaesthesia”, J. Thor. Surg., 25, 435.
12.
TheyeR. A., and TouhyG. F. (1965): “Effect of trimetaphan on haemodynamics and oxygen consumption during halothane anaesthesia in man”, Brit. J. Anaesth., 37, 144.
13.
TordaT. A. (1967): “Oxygenation during one-lung anaesthesia”, Proceedings of the 26th Annual Meeting of the Australian Society of Anaesthetists.
14.
VirtueR. W., PermuttS., TanakaR., PearcyC., BaneH. N., and Bromberger-BarneaB. (1966): “Ventilation and perfusion changes during thoracotomy”, Anesthesiology, 27, 133.
15.
YamamuraH., KaitoK., IkedaK., NakajimaM., and OkadaK. (1969): “The relationship between physiological shunt and cardiac output in dogs under anaesthesia”, Anesthesiology, 30, 406.
